Changing Size from small to big in array or duplication
Yes you can do this using modifiers. You need an array and curve modifier.




Create a curve
Add a sphere
Add an empty (plain axis)
Select Sphere and add an array modifier


turn off Relative Offset
enable Object Offset and chose the empty

move the empty along a axis (possibly the positive x-axis)
scale the empty down a bit, you should see the spheres get smaller towards the end


Select the sphere and add a curve modifier to it. Choose your curve
Depending on the orientation of the curve and the translation of the empty the array may look wrong. In this case move the empty along the other axis. You can also apply the transforms of the sphere and the curve using Ctrl A